In the above fields of monochromatic and color printing, gray scale printing techniques have been used wherein 256 levels of a complete gray scale have been subdivided into typically sixteen (16) or thirty-two (32) levels of a gray table. These subdivided gray levels have been used to control the printing of information of a scanned image into a plurality of pixels to form the reproduced image in one or more color planes. The remainder difference between a printable gray level value of a chosen gray table and the actual scanned pixel value of the image read by a scanner is error diffused into one or more pixels surrounding the just-scanned pixel or super pixel. These error diffusion processes have been described in various detail in my following identified co-pending applications and issued patent which are all assigned to the present assignee and are all incorporated herein by reference.
1. U.S. Pat. No. 4,930,018 issued May 2, 1990 is entitled "Method and System for Enhancing the Quality of Both Color and Black and White Images Produced by Ink Jet Printers".
2. U.S. patent application Ser. No. 353,859 filed May 17, 1989 is entitled "Method and System for Providing Closed Loop Color Control Between a Scanned Color Image and the Output of a Color Printer".
3. U.S. patent application Ser. No. 484,713 filed Feb. 26, 1990 is entitled "Method and System for Reproducing Monochromatic and Color Images Using Ordered Dither and Error Diffusion".
4. U.S. patent application Ser. No. 515,946 filed Apr. 27, 1990 is entitled "Method and System for Enhancing the Quality of Both Color and Black and White Images Produced by Ink Jet and Electrophotographic Printers".
All of my above identified co-pending patent applications disclose and claim new and useful improvements in the fields of both monochromatic and color printing and describe pixel assignment and error diffusion printing processes of the type in which the present invention will prove useful. The error diffusion processes described in these co-pending applications cite, among other things, the Floyd and Steinberg 4-point algorithm and the Stucke 12-point algorithm as being useful for controlling the dispersal of error diffusion into the neighboring pixels surrounding a just-scanned pixel or super pixel and corresponding to the error difference between a printable gray scale discrete level pixel value and the actual input image gray scale pixel data converted by a scanner. These algorithms are operative to control pixel assignment during the error diffusion process in such a manner as to predetermine the exact location of the pixels surrounding a just-scanned pixel or super pixel into which the above error remainder dots are diffused with fixed assigned weights.